This invention is concerned with improvements in high magnification optical apparatus and its object is the elimination of the conventional eye-piece or eye-pieces in such apparatus, so that an observer is not constrained to a precise and often uncomfortable viewing position.
The invention provides in microscopes having no eye-pieces and in screen projectors an optical device producing an enlarged exit pupil which incorporates in the light path from a viewed object to the eye of an observer a series of lenticular faces which are traversed within that path at a speed above persistence of vision, the said faces being formed in such manner as to multiply the angle of light incidence to the angle of light egress as a result of such supra-persistence traverse.
In the case of a microscope it is preferred to use a reflecting system in the light path and the lenticular faces are formed as curved depressions in a polished surface.
In the case of a profile screen projector one may use a light transmission system with the lenticular faces being formed as convex protrusions on the light exit side of a clear plate. It is preferable however for the lenticules to be present on a reflective or translucent disc, which in effect is then the actual viewing screen.
The traversing or scanning of the curved faces is most simply achieved by forming them upon a circular disc which is rotated at appropriate speed.
It has been found, however, that a continuous band-type movement with reflective or translucent lenticular surfaces arranged in echelon or traverse pattern is to be preferred in certain environments where high quality definition is required. This is because of the limitation in the number of faces which can be provided near the centre of a disc.
Binocular vision in depth can be achieved in microscopes by positioning a beam splitter in the light path from a viewed object to the curved reflective faces and lens characteristics may be chosen to give a pair of exit pupils of about 2 inches diameter at the distance apart of average human eyes.